On the day before a snowy, rainy and icy storm was expected to arrive, Washington enjoyed an early December Saturday that provided few signs of what was being predicted.

At Reagan National Airport, where the official readings are made, the day’s overall temperature was normal as of 5 p.m. As of that hour, the day’s average was 42, the normal Dec. 7 reading, according to the National Weather Service.

Rain fell in the early morning, and clouds covered the skies for much of the rest of Saturday. But when the sun went down, it was with a bright splash of orange across the western horizon.

In Alexandria, such major events as the Scottish Walk Parade in the morning and the Lighted Boat Parade in the evening, both drew large crowds.

The sunset and the Alexandria celebrations both seemed to endorse optimism. They seemed to belie the gravity of the warnings suggesting that, within hours, city and suburban roads could become impromptu skating rinks, jeopardizing motorists and pedestrians.

The high temperature was 45, four degrees below the normal figure for the date, but it seemed comfortable enough. The morning’s low temperature was 38, well above freezing and three degrees above normal for Dec. 7.

For hours, as Washington area residents heard predictions of deteriorating conditions, the thermometer provided little hint of such problems.

Many pavements, however, were already covered with ice-melting salt, a sign that warnings had been taken seriously.

As night fell, ominous signs began to appear. The temperature fell below the morning low. By 7 p.m., it had dipped to 37 degrees, just one degree lower than the coldest temperature of the morning.